Free Online Image Optimizer

Compress an image small enough to email, to send in a message, or to put on a web page — without installing anything and without an account. Drop a photograph in and take back a version a fraction of the size, at a quality most people cannot tell from the original.

How it works

Choose a picture, or up to 20 of them at once, at up to 50 MB each. Set it up if you want to: crop it, turn it, darken it, add a caption or a watermark, or choose the format and the width you need. The picture on screen changes as you go, before anything is sent anywhere. Then take one file back, or a zip once you have asked for more than one version.

Nothing is uploaded while you are still deciding. The versions are built at the moment you ask for them, and files submitted to the service are deleted automatically after a short period.

Where the work actually happens

In two different places, and the difference decides what leaves your machine — so it is worth stating rather than glossing over.

Cropping, flipping, rotating, captions, watermarks and the darkening layer are done by your own browser, on your own device. So is turning a vector drawing into a PNG, converting a video clip into an animated GIF, and reading the HEIC files an iPhone produces. That last one is there because most browsers cannot open a HEIC at all, so this page carries its own decoder rather than sending you to find software that can.

The compression itself is done by ImageEngine, the image service this site runs on: resizing a photograph, re-encoding it, and handing it back in whichever format you asked for. It is the same engine that sits in front of commercial sites. Here it is pointed at one file at a time, with the byte count printed beside the result.

What comes back

Format decides more than the quality slider does. One photograph, resized to 1280 pixels wide and asked for in each format this tool can produce — measured, not estimated:

That is the whole argument for converting rather than simply compressing harder: on a photograph, AVIF at the same width is less than half the JPEG. PNG and GIF are on the list because sometimes the form you are filling in will accept nothing else, and a tool that cannot produce the format you need is no use whatever its byte count.

Step-by-step guides

Every tool here has an illustrated walkthrough — what the controls do, what the numbers mean, and what to watch out for, with screenshots of the real thing. Browse all the guides, or follow the link at the foot of any tool page.

Every tool

The tool above does all of it. Each page below is the same tool, set up for one job and described in the words people use for it:

Common questions

Does it cost anything? No. There is no account, no watermark on what you take back, and nothing waiting behind the download button. The site carries advertising; that is the whole of the business model.

What happens to the pictures I send? They are used to produce the versions you asked for and nothing else, and they are deleted automatically after a short period. The privacy notice is the binding version of that sentence.

How big a file can I send? 50 MB each, and up to 20 at a time. A batch takes one set of settings for all of them.

Which format should I choose? WebP or AVIF for a web page, JPEG when something else has to open it, PNG for screenshots of text and line art where the hard edges matter. The format guide works through what each one is good at.

Will it ruin the quality? Most of the saving comes from resizing rather than from compression, and a photograph shown at 1280 pixels does not benefit from carrying 4,000. Every result is reported with its before and after size, so you can judge it rather than take our word.

What can you use it for? · Step-by-step guides · Image formats explained · Contact us